Bicycle



(No Model.) v A2 sheetssheen 1.

' J. RAU.

BICYCLE.

No. 571,793. Patented Nov. 24, 1896.

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J. RAU. BICYCLE.

No. 571,793. Patented Nov. 24, 1896.

QZ/Ja? Y Z22/vera n gm cff/ M I w C6, g2? Mw Unirse Stains arrgsrrterreni lOiIN RU, OF CIIICAGO, ILLINOIS, ASSIGNOR TO FRANK L.SA'XLISBURY, JOHN SALISBURY, AND CLARENCE lll. BRINCKIRIIOFF, OF SI/ XMEPLACE.

BICYCLE.

SPECFICATION forming' part of Letters Patent No. 571,793, dated November24, 1896.

Application led January 28, 1895. Serial No. 535,405. (No model.)

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Iie it known that I, JOHN RAU, a citizen of the United States, residingat Chicago, in the county of Cook and State of Illinois, have invented acertain new and useful Improvement in Bicycles, of which the followingis a full, clear, concise, and exact description, reference being had tothe accompanying drawings, forming a part of this specification.

lily invention relates to the drivin g meehan ism of bicycles of theclass usually known as safetiesj7 in which the main drivingsha-f t uponwhich the cranks are mounted is provided with a sprocket-Wheel carryinga sprocket-chain which runs over a sprocketpinien provided on the shaftofthe rear Wheel.

My invention consists in the novel construction, arrangement, andcombination of parts, as hereinafter fully described, illustrate-d inthe dra-Wings, and'pointed out in lthe appended claim.

My invention will be more readily understood by reference to theaccompanying drawings, forming a part of this specification, in Which-Figure 'l is a horizontal section of the driving mechanism embodying myinvention, taken on line l l of Fig. 2. Fig. 2 is an elevation of thedriving mechanism. Figs. 3 and 4 are details of the cams working withinthe cani -grooves of the symmetrically-disposed cam-plates. Figs. 5 and6 are diagrammatic illustrations showing the relation of the parts whenthe cranks occupy a horizontal position. F1' g. is a diagrammaticalillustration showing the relation of the parts when ihc cranks occupy avertical position.

Like letters refer to like parts throughout the several figures.

The driving gear-Wheel o is mounted rigidly upon the shafted, which ismounted upon and supported bythe bearing l), carriedupon the frame b ofthe machine.

c cj indicate guideways, one of which at least should be removablymountedupon one end of the shaft a, (in order that the parts might bearranged Within the hanger of the 1nachine,) as by screwing saidguideway upon the shaft, as shown, While the other guide- Way might beformed integrally with the other end of the shaft. 'These gniden-'aysaccommodate the treadle-levers d d', which are adapted to bereciprocated Within said guideways as the pedals are rotated. The guide-Ways are preferably made as shown in Fig. l, wherein cylindricalportions c:3 c4 are extended froln the shaft a". Ball-bearings areprovided in the cylinders to lessen the friction upon the pedal-levers.Cam-plates e c" are mounted symmetrically and preferably upon the frameof the machine, as shown. These cam-plates, as hereinbefore stated, arepreferably circular, in which case they are disposed eccentrically withrelation to the drivi ng-shaft.

The treadle-levers d d are provided upon one end with the pedals d? d3and npon the other end with cams d'1 (Z5. The cams are preferably madein the manner shown in Figs.

3 and 4, wherein are illustrated a cam-groove d of a cam-plate, one endof a treadle-lever d, and the cam provided with recesses dl, in whichare placed the bearing-rollers ds.

In driving bicycles it is desirable to have greater leverage upon thedownstroke of the pedals, and the point at which it is desired to havethe greatest leverage is at the middle of the downward stroke or, inother Words, at that point when the pedal reaches a horizontal planecoincident with the shaft. IvVith this end in View I place thecam-plates with their points of greatest eccentricity with relation tothe shaft upon the horizontal plane and in frontof the shaft.

Referring now more particularly to Figs. 5, G, and 7, it will be seenhow the distance between the shafts of the pedals and the fulcrnni ofthe pedal-levers or the center of the driving-shaft varies.

In Figs. 5 and (l the pedals are shown in a horizontal plane coincidentwith the axis of the shaft, the lever CZ in Fig. being shown in its mostextended position with relation to its fnlerum, While the saine lever isshown in Fig. l) at the shortest distance from its fulcrum. The centersof the shaft and the eccentric cam-plates occupying a fixed positionwith relation to each other, it will be seen that the distance betweenthe center of the shaft and the pivotal point between the pedal-leversand the cams varies as the pedals are rotated. Tracing the travel of thepedal (Z2 IOO about the shaft of the driving sprocket-wheel, when thepedal occupies the position shown in Fig. 5 thc distance between thepivotal connection of the cam with the pedal-lever and the shaft of thedriving sprocket-wheel` is less than when the cam and pedal occupy anyother position, since the point of greatest eccentricty of the cam-plateis between the pedal and the driving-shaft. The pedal d2 is thusfarthest removed from the shaft of the driving sprocket-wheel, therebyincreasing the leverage at the point desired.

When the pedals are brought in a vertical line, as shown in Fig. 7,the;T are equidistant from the center of the driving-shaft. Since thecenter of the eccentric cam-plates and the center of the driving-shaftare on the saine horizontal line, any vertical line intersecting theline of travel of the pivotal connections between the cams and thetreadle levers through the center of the d rivingshaft will interceptsaid line of travel at points equidistant from the center of the shafton opposite sides of said horizontal line. lVhen the pedal cl2 has madea half-revolution, the distance between its shaft and the driving-shaftis brought to a minimum, as shown inY Fig. G, since the center of thedriving-shaft is now between the point of greatest eccentricity and thecenter of the shaft of the pedal.

I am aware of Letters Patent of the United States No. 96,124 and LettersPatent of Great Britain No. 972 of lSSl and No. 9,207 of 1888 and do notclaim anything therein shown or described.

I would say that in order that the ballbearings within the guideways c cmay be as n early d ust-proof and frictionless as possible, I providethe dust-caps cS at the ends of the said guideways and inclosing theantifrictionballs, as shown.

In a prior application I have illustrated mechanism whereby the distancebetween the shaft of the pedal-lever and the shaft of the drivingsprocket-wheel has been varied. therefore limit my claim in the presentinstance to the combinations of mechanisms as follows.

IIaving described my invention, I cla-im as new and desire to secure byLetters Patent- In a bicycle, the combination with the frame thereof andthe driving-shaft, of cylindrical guideways on the ends of the saidshaft, annular rings secured to the frame intermediate the saidguideways, said rings beinP arranged eccentrieally to the driving-shaftand being provided with grooves in their outer faces, pedal-leverspassing sliding-ly through the guideways and having their ends` oppositeto those which carry the pedals, bent inwardly, a block mounted uponsaid bent end of each lever and curved to correspomi with the curvatureof the grooves in the rin and seating within said groove, said blocksbeing provided with recesses di in their opposite faces and adjacent totheir opposite ends, antifriction-rollers d8 seated in said rccesses andbearing upon the walls of the grooves of the rings, antifriction-ballsarranged within the cylindrical guideways at opposite ends thereof andbearing upon the pedal-levers, and dust-proof caps upon the ends of saidgnideways and inclosing the said balls and through which caps thepedal-levers slidingly pass, as speciiied.

In witness whereof I hereunto subscribe in y naine this 23d day ofJanuary, A. D. lSD.

JOHN RNC. Witnesses:

GEORGE P. BARTON, JNO. E, SALIsBURY.

